Oversized support list on TPLink Archer C60 devices about firmware-utils HOT 2 OPEN

from firmware-utils.

It looks like the firmware partition ends at 0x7d0000, while soft-version only starts at 0x79d9500. That leaves a bit of empty space (0x9500 or 38k bytes). Normally stock firmware is able to handle "re-partitioning", so I think it might be possible to resize soft-version to start at 0x7d9000 with a size of 0x600 bytes. (or e.g. 0x9400/0x200). Only one way to find out: just try it.

My approach would be to first dump the original flash contents, and validate that the empty space in the partition table is indeed unused. (Empty flash is all 0xff).
Then you could try with a custom modified factory image. You can make a change firmware-utils, then use git format-patch to export it and place it in your openwrt tree at tools/firmware-utils/patches/ (you will probably need to create this directory).

Please make sure you have way to dump and write flash using external means like an SOIC-8 clip, or you may end up with a bricked device if this approach doesn't work.

from firmware-utils.